Substituent-Dependent Reactivity in the Photodimerization of N-Substituted Dibenz[b,f]azepines
作者:Jens Querner、Thomas Wolff、Helmut Görner
DOI:10.1002/chem.200305199
日期:2004.1.5
The photoprocesses of a series of N-substituted dibenz[b,f]azepines (iminostilbenes) were studied by absorption and emission spectroscopy, by laser flash photolysis, and by preparative irradiation with NMR analysis. In solutions, 2pi+2pi photodimers of N-cyano and N-acyl dibenzazepines are formed via the triplet state upon acetone- or benzophenone-sensitized energy transfer. T-T absorption spectra
通过吸收和发射光谱,激光闪光光解以及通过NMR分析制备辐射研究了一系列N-取代的二苯并[b,f]氮杂苯(亚氨基苯磺酸)的光过程。在溶液中,N-氰基和N-酰基二苯并ze庚因的2pi + 2pi光二聚体在丙酮或二苯甲酮敏化的能量转移后通过三重态形成。测量了TT吸收光谱并确定了吸收系数。三重态能量转移对于不二聚的N-烷基二苯并ze庚因同样有效。讨论了后者情况下npi *字符的激发态,以合理化不同的反应性。尽管21种二苯并ze庚因衍生物的体系间交叉可忽略不计,但在浓溶液中直接激发后仍会形成N-酰基和N-氰基二苯并ze庚因的光二聚体(0。01-0.1 mol dm(-3))以及固态。整个过程中发现了对光二聚体的选择性抗构型。